Autonomous bioelectric physiological signal acquisition device

Abstract

A method for bioelectric physiological signal acquisition includes: /a/ providing an autonomous bioelectric physiological signal acquisition device including an electrode and an acquisition chain associated to the electrode, /b/ acquiring an analog signal representative of a bioelectric physiological signal with the electrode, /c/ amplifying the analog signal by an amplification factor via a programmable analog amplifier of the acquisition chain, /d/ converting the amplified analog signal in a digital signal via an analog digital converter of the acquisition chain, /e/ processing the digital signal to determine whether the digital signal is considered saturated, if the digital signal is considered saturated, /f/ selecting, in a list of predefined amplification factors, an amplification factor lower than the amplification factor currently applied to the digital signal by the programmable analog amplifier, and /g/ updating the amplification factor of the programmable analog amplifier to the selected amplification factor.

1 - 14 . (canceled) 
     
     
         15 . A method for bioelectric physiological signal acquisition comprising:
 /a/ providing an autonomous bioelectric physiological signal acquisition device comprising at least one electrode and at least one acquisition chain associated to said at least one electrode,   /b/ acquiring at least one analog signal representative of a bioelectric physiological signal by means of said at least one electrode,   /c/ amplifying said analog signal by an amplification factor by means of a programmable analog amplifier ( 6 ) of said at least one acquisition chain,   /d/ converting said amplified analog signal in a digital signal by means of an analog digital converter of said at least one acquisition chain,   /e/ processing said digital signal to determine whether said digital signal is considered saturated,   if said digital signal is considered saturated,   /f/ selecting, in a list of predefined amplification factors, an amplification factor lower than the amplification factor currently applied to the digital signal by the programmable analog amplifier, and   /g/ updating the amplification factor of the programmable analog amplifier to the selected amplification factor.   
     
     
         16 . The method of  claim 15 , wherein, steps /b/ to /g/ are reiterated continuously during a period of acquisition of the device. 
     
     
         17 . The method of  claim 15 , wherein if the amplification factor currently applied to the digital signal by the programmable analog amplifier is equal to the lowest amplification factor in the list of predefined amplification factors and the digital signal is considered saturated, the analog digital converter and/or the programmable analog amplifier of the acquisition chain are powered out and steps /d/ to /g/ are not performed anymore. 
     
     
         18 . The method of  claim 17 , wherein if an analog digital converter and/or a programmable analog amplifier of an acquisition chain has been powered out, the following steps are periodically performed:
 /h/ powering said analog digital converter and/or programmable analog amplifier,   /i/ performing at least one iteration of steps /b/ to /e/,   if the digital signal obtained from said at least one iteration is not considered saturated,   /j/ setting back on said analog digital converter and/or programmable analog amplifier for further iterations of steps /b/ to /e/ until said digital signal is considered saturated,   or if the digital signal obtained from said at least one iteration is considered saturated,   /k/ powering out said analog digital converter and/or programmable analog amplifier for further iterations of steps /b/ to /g/ until step /h/ is performed again.   
     
     
         19 . The method of  claim 15 , wherein, if the amplification factor currently applied to the digital signal by the programmable analog amplifier is not equal to the highest amplification factor in the list of predefined amplification factors, the following steps are periodically performed:
 /l/ selecting, in the list of predefined amplification factors, an amplification factor higher than the amplification factor currently applied to the digital signal by the programmable analog amplifier,   /m/ updating the amplification factor of the programmable analog amplifier to the selected amplification factor, and   /n/ performing at least one iteration of steps /b/ to /g/.   
     
     
         20 . The method of  claim 15 , wherein to determine whether a digital signal is considered saturated,
 a portion of the digital signal is stored in a buffer memory, preferably a portion with a duration of at least one second,   a ratio of saturated values to non-saturated values in the stored digital signal is computed,   said ratio is compared to a predefined threshold, and   if said ratio is over said predefined threshold, the digital signal is considered saturated.   
     
     
         21 . The method of  claim 15 , wherein if the digital signal is considered saturated an amplification level change indicator is written in a memory of the device together with an associated time stamp, and preferably, if the analog digital converter of the acquisition chain is powered out a channel power out indicator is further written in said memory together with an associated time stamp. 
     
     
         22 . The method of  claim 15 , wherein the provided autonomous bioelectric physiological signal acquisition device comprises a plurality of electrodes and a plurality of respective acquisition chains respectively associated to said electrodes,
 wherein said plurality of electrodes acquires a plurality of respective analog signals representative of a plurality of respective bioelectric physiological signals,   wherein said plurality of analog signals are amplified by a plurality of amplification factor by means of a respective plurality of programmable analog amplifier of said plurality of acquisition chains,   wherein said plurality of amplified analog signals are converted in a respective plurality of digital signals by means of a respective plurality of analog digital converters of said plurality of acquisition chains,   wherein said digital signals are independently processed to determine whether each digital signal of the plurality of digital signals is considered saturated,   and wherein for each digital signal of the plurality of digital signals that is considered saturated,   an amplification factor, lower than the amplification factor currently applied to said digital signal by the programmable analog amplifier associated to said digital signal, is selected in a list of predefined amplification factors, and   the amplification factor of the programmable analog amplifier associated to said digital signal is updated to the selected amplification factor.   
     
     
         23 . An autonomous bioelectric physiological signal acquisition device comprising
 at least one electrode able to acquire an analog signal representative of a bioelectric physiological signal,   at least one acquisition chain associated to said at least one electrode and comprising:   a programmable analog amplifier able to amplify an analog signal by an amplification factor, and   an analog digital converter able to convert an amplified analog signal in a digital signal,   a microcontroller and a memory able to   process a digital signal to determine whether said digital signal is considered saturated, and   if said digital signal is considered saturated,   select, in a list of predefined amplification factors, an amplification factor lower than the amplification factor currently applied to the digital signal by the programmable analog amplifier, and   update the amplification factor of the programmable analog amplifier to the selected amplification factor.   
     
     
         24 . The device according to  claim 23 , the device comprising a plurality of electrodes and a plurality of respective acquisition chains respectively associated to said electrodes. 
     
     
         25 . The device according to  claim 23 , wherein the acquisition chains are integrated in a single monolithic chip incorporating programmable analog amplifiers and analog digital converters. 
     
     
         26 . The device according to  claim 23 , wherein the analog digital converters are of the 24 bit delta-sigma type with an output data rate between 250 SPS and 32 kSPS. 
     
     
         27 . The device according to  claim 23 , wherein the device comprise at least one battery powering at least the at least one acquisition chain, the microcontroller and the memory. 
     
     
         28 . The device according to  claim 23 , further comprising a microprocessor able to receive the digital signal from the microcontroller and to process said digital signal.